Process for recovering support from photographic film

Abstract

A process for recovering a support from a photographic film is disclosed. The photographic film comprises the support and an undercoating layer provided thereon. The support is made of cellulose triacetate film base. The undercoating layer contains gelatin and cellulose nitrate. According to the present invention, the process comprises the steps of: (I) treating the photographic film with an aqueous solution of a surfactant; and then (II) treating the photographic film with an aqueous solution of a protease to remove the undercoating layer from the support. The aqueous solution of the protease used at the step of (II) preferably further contains an anionic surfactant. It is also preferred that the process further contains the step of (III) treating the recovered support with an aqueous solution of hydrogen peroxide to bleach the support.

We claim: 
     
       1. A process for recovering a support from a photographic film which comprises the support and an undercoating layer provided thereon, said support being made of cellulose triacetate film base, and said undercoating layer containing gelatin and cellulose nitrate, wherein the process comprises the steps of: (I) treating the photographic film with an aqueous solution of a surfactant; and then   (II) treating the photographic film with an aqueous solution of a protease to remove the undercoating layer from the support.     
     
     
       2. The process for recovering a support from a photographic film as claimed in claim 1, wherein the surfactant used at the step of (I) is a nonionic surfactant. 
     
     
       3. The process for recovering a support form photographic film as claimed in claim 1, wherein the surfactant used at the step of (I) is a polyethylene glycol ether. 
     
     
       4. The process for recovering a support from a photographic film as claimed in claim 1, wherein the surfactant used at the step of (I) is contained in the aqueous solution in an amount of 0.1 to 5 weight %. 
     
     
       5. The process for recovering support from a photographic film as claimed in claim 1, wherein the aqueous solution of the surfactant used at the step of (I) is an alkaline solution. 
     
     
       6. The process for recovering a support from a photographic film as claimed in claim 1, wherein the aqueous solution of the surfactant used at the step of (I) is an alkaline solution having a pH value int he range of 8 to 12. 
     
     
       7. The process for recovering a support from a photographic film as claimed in claim 1, wherein the photographic film is treated at the step of (I) at a temperature in the range of room temperature to 70° C. 
     
     
       8. The process for recovering a support from a photographic film as claimed in claim 1, wherein the photographic film is treated at the step of (I) for 10 to 100 minutes. 
     
     
       9. The process for recovering a support from a photographic film as claimed in claim 1, wherein the photographic film is washed with water to remove the aqueous solution of the surfactant between the steps of (I) and (II). 
     
     
       10. The process for recovering a support from a photographic film as claimed in claim 1, wherein the protease used at the step of (II) is contained in the aqueous solution in an amount of 0.01 to 2.0 weight %. 
     
     
       11. The process for recovering a support form a photographic film as claimed in claim 1, wherein the aqueous solution of the protease used at the step of (II) further contains an anionic surfactant. 
     
     
       12. The process for recovering a support from a photographic film as claimed in claim 1, wherein the aqueous solution of the protease used at the step of (II) further contains a salt of a sulfuric ester of a higher alcohol as an anionic surfactant. 
     
     
       13. The process for recovering a support form a photographic film as claimed in claim 1, wherein the aqueous solution of the protease used at the step of (II) further contains an anionic surfactant in an amount of 0.1 to 5 weight %. 
     
     
       14. The process for recovering a support from a photographic film as claimed in claim 1, wherein the photographic film is treated at the step of (II) at a temperature in the range of room temperature to 70° C. 
     
     
       15. The process for recovering a support form a photographic film as claimed in claim 1, wherein the photographic film is treated at the step of (II) for 10 to 200 minutes. 
     
     
       16. The process for recovering a support from a photographic film as claimed in claim 1, wherein the photographic film is washed with water to remove the aqueous solution of the protease after the step of (II). 
     
     
       17. The process for recovering a support from a photographic film as claimed in claim 1, wherein the process further contains the step of (III) treating the recovered support with an aqueous solution of hydrogen peroxide to bleach the support. 
     
     
       18. The process for recovering a support from a photographic film as claimed in claim 17, wherein hydrogen peroxide used at the step of (III) is contained in the aqueous solution in an amount of 1 to 20 weight %. 
     
     
       19. The process for recovering a support from a photographic film as claimed in claim 17, wherein the recovered support is treated at the step of (III) at a temperature in the range of room temperature to 90° C. 
     
     
       20. The process for recovering a support from a photographic film as claimed in claim 17, wherein the recovered support is treated at the step of (III) for 30 to 150 minutes.